Aircraft require a high level of maintenance and care to assure their safe use. Most aircraft comprise a metallic fuselage that is held together by metallic rivets. Both the fuselage and the rivets may occasionally require scanning to determine if weaknesses have developed within the metal.
In some circumstances, it is beneficial to be able to scan the fuselage of the aircraft without having to remove the rivets or disassemble the aircraft. Further, in some circumstances it is beneficial to be able to scan the surface of the fuselage immediately surrounding a feature, such as a rivet, without having to scan the feature itself.
Difficulties may arise in attempting to scan around a feature and still maintain a sensor sufficiently close to the surface to be scanned. Another difficulty may be keeping the sensor parallel to the surface that is being scanned while scanning around a feature.